In a wireless communication system, in order to improve the data transmission rate and the system throughput, MIMO technologies can be used. One or more data streams are transmitted via an MIMO channel in a manner capable of obtaining the largest system throughput of the system data transmission, which can reach excellent system performance. Simultaneously, a User Equipment (UE) may measure the MIMO channel and report channel state information to a base station. The channel state information comprises a Rank Indicator (RI), a Precoding Matrix Index (PMI), a Channel Quality Indicator (CQI) of each data stream and the like. The CQI of each data stream is may indicate a receiving Signal to Noise Ratio (SNR) and corresponding Coding Rate (CR) of the data stream.
In a Long Term Evolution (LTE) system, the manner of reporting channel state information by a UE comprises periodic reporting and aperiodic reporting.
Wherein, the periodic reporting is performed by the UE through a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH). Specifically, the reporting is performed by the PUCCH when the UE has no PUSCH resources at the periodic reporting time, and the reporting is performed by the PUSCH when the UE has PUSCH resources at the periodic reporting time. After the UE accesses to a base station, the base station may configure PUCCH resources and reporting period to the UE.
The aperiodic reporting is performed by the UE through the PUSCH. Reporting the channel state information through the PUSCH is divided into two situations: the channel state information may be multiplexed with UpLink Shared Channel (UL-SCH) data; and the channel state information (namely, without UL-SCH data) is reported independently. Currently, no specific scheme is provided concerning when the base station requires the UE to perform the aperiodic reporting, such that the base station cannot sufficiently obtain the channel state information reported by the UE; meanwhile, PUSCH resources cannot be rationally used.